Sound reproducing diaphragm



July 2,1935 AWLEY y 2,006,830

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Patented July 2, 1935 I Z 'UNITED STATES PATENT OFFICE aooasso soUNp aanoDUcING DIAPHBAGM Jesse B. Hawley, Geneva, Ill.`

Application December 24, 1930,. Serial No. 504,536

13 Claims. (Clisi-sz) Among the objects of the invention is to prosired, the member may be left uncompressed or vide a novel sound producing or reproducing diauncalendered. phragm or diaphragmatic member and a novel -Another object of the invention is to immethod of making or producing it. pregnate the sound producer with moisture or I To obtain a sound producingor reproducing water proong material or substance, whereby I diaphragm capable of producing or reproducing the acoustic properties of the diaphragm will sound true and faithful to the original sound not Change With the humidity f the SOlind to be reproduced, it is necessary that the diamedium, such as the air of the atmosphere. The phragmatic member be as light in weight as impregnation may be Of different degrees Over l0 possible and not subject to a natural period or the diaphragm, S0 that diierent pi'tS 0i the 10v fundamental frequency, yet sufilciently stiff to diaphragm may be emcientiy responsive t0 the setup the proper waves in the sound medium. diierent periods of the audible range of sound An-object orthis invention is to produce such to the end of making the diaphragm substana. sound producer or reproducer which will have tiliy ln-fundamental in periods. 1I asubstantially even response curve, where all Y A further Object iS t0 provide a novel process l5 sounds of the audible range will be produced or 0f making Sileh a diabhram BS by dePOSitinB 'reproduced with substantially equal emciency. the fibres of a bath on a porous former. apply- In an illustrative embodiment of the inveni118 Pressure 0n the Part 0f the brOiiS blank tion the sound producer `is preferably of moulded t0 be made thinner 01' fieXule. With 0r Without fibrous material. It is made in one integral impregnting lthe bink, and nishing. 8S by 20 piece and without any seam. It may be of any drying. compressing and the like. The pressing desired shape, as pyramidal, cone shaped, comay be effected while the blank is wet, or after noidal, cissoidal and other similar shapes, with the blank has been dried, 01' after the blank has en integral basal flange by which the diophregbeen treated.

26 matic member may besupported. It is very Other Objects, advantages. epabilities, fe- 25 thin and very light in weight to reduce to a mintures and DI'OCeSS Steps' are COmDrehended by imum, the mass inertie or momentum thereof. the invention as will later appear and as are 1nf The flange is preferably made with a border porherently possessed thereby l tion for retention/by a\support` or holding means, Referring t0 the drawing;

.30 and a thinner portion between the border por- Figure 1 iS a Vertical SeetiOnal View thrOuSh a 3Q tion and the body part 0f the device, whereby former and a moulded blank'of-ilbrous material. the freedom or vibration of the sound producer Figure 2 is a similar view of compressing means may be greatly enhanced, the thinner portion and a blank t0 be eOmpreSSed at the juncture' mentioned being very easily flexed or having between the bOdy 0r cone pOltiOn and the basal increased iiexure.` This portion is also prefer- 0r flange portion 0f the diphragmtic member- 35 ably undulated to aid the pliability or flexure at Fiiire 3 iS e fragmentary SeetiOnl View 0n an the region above indicated. enlarged scale through the compressing means, This thinner portion may be and preferably and the compressed portion 0f the diphragmatic v is effected by compressing or compacting the member.

40 fibrous material at the juncture between the Figure 4 iS a tOD Pian View 0f e iiIiiShed blank. 40

` body portion or cone part of the diaphragmatic Referring now more in detail to the drawing, member, and the basal flange. In the process the diaphragm 0f this inVentiOn iemade by deof moulding, the libres arepreferably deposited POSiting breS 1111011 DOI'OUS former having on a porous former to form a, blank. The thickpores or apertures 2, from a bath of fibrous maness of the deposit, is substantially uniform terial in a liquidsuch as water. The former l, 45 throughout the blank. The blank, either while as in the illustrative construction, is of any destill wet or moist, or after it is dried, is then sired shape, and the particular shape of the subjected to compression, as between dies, or blank to b e moulded, has a cap 3 which may be rollers, or the like; for compressing or compacteither closed'or porous as desired, and a flange ing the fibres at the region mentioned. If de- I which is also porous. Between the ange and 5 sired, the whole diaphragmatic Vmember may be the body portion I the former is preferably procalendered or compressed to compact the libres, vided with an undulated or corrugated juncture and additional pressure applied at the juncture` portion 5. This former may llt into a container between the body and basal flange portions, 6 of the bath. Within and below the former n.

u for the purpose above'mentioned. Or, if departial vaccum may be created so that the liqu uid of the fibrous bath may be sucked through the pores 2 of the former and cause a deposit of flbres 1 upon the former as shown in Figure 1. These fibres are preferably deposited with substantially uniform thickness throughout the whole blank. During the sucking action, the bath may be and preferably is agitated and vibrated to maintain the bres in suspended and dispersed condition, and also to aid in the proper laying and interlacing of the fibres deposited and accreted on the former.

After the blank has been completely formed in the manner above described, the blank may be removed from the former and` placed upon a compressing member, such as a die 'la having the proper and desired configuration or-contour as clearly shown in Figure 2. It is preferable that this compressing member have a counterpart corresponding to'the corrugatedportion 5 of the former and to lit properly with the corrugated portion 8 of the blank. A second compressing member, such as a die 9 or a roller 9a having a counterpart undulated or corrugated surface l0 or Il!a is made to engage with the opposite surface of the corrugated portion of theblank as clearly shown in Figures 2 and 3. The compressing members are then made to function so as to compress the fibrous material therebetween for the purpose of compacting such fibres and also to render the thickness of` the compressed portion of the fibres less than the body portion Il and the flange portion l2 of the diaphragmatic member. In this way the compressed juncture will be made more durable and lasting although the same is made more pliable or flexible by reason of making the material thinner than the body and ange of the blank. By making the juncture also undulated or corrugated, the flexibility or pliability of the juncture is enhanced.

If desired, before the compression of the juncture ls effected the whole blank may be compressed to compact the bres, and then the juncture given an additional pressure or compression to effect the desired thinner and tougher portion as above described.

It is preferable to treat the blank either when it is soft and wet or after it has been dried, with some impregnating material which has moisture or water proofing properties. As for example, the apical or central portion of the diaphragm or cone may be impregnated with such substances as duco, lacquer or like similar substances. The remainder of the diaphragm may be impregnated with such substances as rubber cement or other water proofing material so that this part of the diaphragm will be more supple or limber than the central portion of the diaphragm. The central portion of the diaphragm is preferably impregnated with a denser substance so that such central portion will be stiffer than the remainder of the diaphragm. The basal flange portion may be impregnated with such material as rubber cement, latex and other like and similar materials. The impregnation may vary over different areas so that the stiffness and flexibility may vary accordingly.

If desired, the impregnating material might be mixed in the pulp bath so that when the fibres are deposited, they will also carry with them the proofing material. Such material as asphaltum, latex, resin, size and sulphate of aluminum may be used. These may help to toughen and water proof the material of the diaphragm so that the diaphragm will have the desired acoustic ohar acteristics mentioned above. may be used.

The diaphragm is of extremely light Weight, and very flexible in the flange portion thereof, particularly at the thin portion or juncture between the cone or body portion and the flange portion. f

In use a hollow cylinder is attached to the neck I6 and carries a coil of ne wire located in an annular magnetic gap of a dynamic type of actuator. 'I'he border I2 is clamped in a fixed part of the sound reproducing mechanism, so that the diaphragm or cone is suspended by way of the thin corrugated juncture 8 of the diaphragmatic member. Suitable flexible means may be connected at the neck' portion I6 for movably supporting that end. Y

As the cone portion is vibrated, the thin corrugated band or juncture 8 permits its freedom of vibration by reason of the thinness and undulatory form of that portion thus giving great flexibility and pliability at the parts located between the flange l2 which is held in fixed position and the moving cone or body l of the diaphragmatic member.

In this art, difficulties are met in which a diaphragm of this kind usually has some fundamental period or natural frequency of vibration at which some waves of the same period Iwill be more efliciently rendered or reproduced than others of the audible range. In making a portion of the diaphragm stiier than another portion, certain frequencies of the audible range will be more efficiently transmitted or emitted by the stiffer portion, while the other frequencies will be more efficiently transmitted by the less stiff portion of the diaphragm. As for example, if the diaphragm be of low natural period tendency, it would tend to reproduce low frequencies more efficiently. By stiffening a portion, that portion will transmit -certainl frequencies, such as the high frequencies, more etliciently, and by making other portions more flexible, the latter portions will transmit other frequencies, such as low frequencies, more eiliciently. In this way the whole audible range may be efficiently reproduced.

By making the diaphragm of integral material, such as moulded fibrous substances, certain disadvantagesare avoided, such as those that are present in the rolled and seamed cone, or the stretched cone. In the latter forms, the material used is placed under strains and stresses which affect the acoustic properties of the sound reproducer. By the present invention, the shape of the diaphragm is that originally produced and there is no strain nor stress of any kind to affect its acoustic properties. The compressing of the connecting portion or band between the cone and the flange does not produce a distortion or stress or strain in the body portion of the cone from which the sound Waves are sent forth in the sound transmitting medium, such as the atmosphere. Moreover, the diaphragm of the present invention isV more or less porous even after it is impregnated and its porosity seems to have the characteristic of engaging the sound transmitting medium without any tendency of slippage and hence loss of sound reproduction.

This disclosure-is a continuation in part of my co-pending application Ser. No. 489,835, filed October 20, 1930, now Patent No. 1,872,583 granted August 16, 1932.

While I have herein described and upon the Any kind of nbre drawing disclosed an embodiment of the invention and a process of producing it, it is to be understood that the invention is not limited thereto, but may comprehend other structures, arrangements of parts, details, features and process steps without departing from the spirit thereof.

Having thus disclosed the invention,

l claim:

1. A sound producer of integral molded fibrous material, comprising a vibratile portion, a sup porting portion, and a connecting portion, said connecting portion being thinner and more compact than the remainder of said producer.

2. A sound producer of integral molded fibrousv material, comprising a vibratile portion, a supporting portion, and a connecting portion, said connecting portion being flexible and compressed and thinner than the remainder of said producer.

3. A sound producer of integral molded fibrous material, comprising'a body portion, a basal portion, and a compressed thinner portion therebetween for enhancing the freedom of vibration of the producer.

4. A sound producer of integral molded fibrous material, comprising a body portion, a basal portion, and a compressed thinner and undulated portion therebetween for enhancing the freedom of vibration of the producer.

5. vA sound producer of integral molded fibrous material, comprising a cone portion, a basal flange portion, and a thin flexible connecting portion, said connecting portion being composed of compressed fibres.

6. A sound producer of integral molded fibrous material, comprising a cone portion, a basal flange portion, and a. thin flexible connecting portion, said connecting portion being undulated and composed of compressed ilbres.

7. A sound producer comprising a diaphragmatic member, a exible portion and a border, saidflexible portion being thinner than the relmainder of said member and composed of com- 9. A sound producer comprising a diaphrag matic member having a central vibratile portion, a marginal supporting portion, and an intermediate flexible portion of thinner and more compacted material than the remainder of said member.

10. A sound reproducing seamless diaphragm initially formed integrally throughout of accretions of fibrous material, comprising a cone shaped body and an integral supporting flange, the juncture of the body and flange being compressed to render the same pliant and durable whereby the cone shaped body may be controllably vibrated to reproduce sound.

ll. A sound reproducing seamless diaphragm initially formed integrally throughout of accretions of fibrous material, shaped body and an integral supporting flange, the vjuncture of the body and flange being undulated and compressed to render the same pliant and durable for controllable articulation of the body and flange and whereby the cone shaped comprising acone Iii body may be controllably vibrated to reproduce sponsive to the lower frequencies of the audible range of sound reproduced by said body, the more rigid apical portion of the body being emciently responsive to the higher frequencies of the audible range of sound reproduced by said body, the juncture of the body and flange being thinner and more compact and more pliant than the body and flange for freedom of vibration of the body as a whole when reproducing sound.

13. A sound reproducing seamless diaphragm initially formed integrally throughout of accretions of fibrous material, comprising a cone shaped body and an integral supporting flange, the apical portion of the cone shaped body being treated with stiffening material to render said portion more rigid than the remainder of the body andfor making the treated portion enlciently responsive to the higher frequencies of the audible range of sound reproduced'thereby, said remainder being treated to render it supple whereby said treated remainder is efficiently responsive to the lower frequencies of the audible range of sound reproduced by said body, the juncture of the body and flange being compressed, thinner and more pliant than the body and flange for freedom of vibration of the body as a wholewhen reproducing sound.

JESSE B. HAWLEY. 

